A double-blinded randomised controlled study of fluid restriction versus liberal fluid during induction of labour: A pilot study.

Background: Excess intravenous fluid for women requiring an induction of labour may adversely affect the duration of labour and maternal/neonatal outcomes.

Aims: This study aimed to determine the difference in duration of labour and outcomes with a low background infusion rate, compared to liberal background intravenous fluid management.

Materials and methods: A double blind randomised controlled pilot study was performed on 200 women who underwent induction of labour at a single institution. Women were randomised to an intravenous rate of 40 mL/h versus 250 mL/h of Hartmann's solution. Fluid boluses were strictly controlled to limit bias. This trial was registered with the Australian clinical trial registry: ACTRN12621001298808.

Results: Analysis of the total amount of fluid received showed good separation with Group 1 (40 mL/h) receiving 1,736 mL less than Group 2 (250 mL/h), median (interquartile range) 841 mL (458, 1691) versus 2,577 mL (1620, 4326) (P < 0.001). Median duration of labour was shorter in Group 1 by 24 min (P = ns). Subset analysis of nulliparous women showed that duration of labour was shorter in Group 1 by 83.5 min (P = ns).

Conclusion: As this was a pilot study, a significant difference in duration of labour or secondary outcomes was not seen. Given the increasing numbers of nulliparous women having an induction of labour, potential for adverse maternal and neonatal outcomes and the associated higher rate of operative birth, this study guides power calculations and supports proof of concept for future research into optimum fluid management during induction of labour for these women.